Products and processes, including machines, generally perform at least one of four functions related to energy. They can convert energy, transmit energy, contain energy or direct energy. Recognizing that energy can be either destructive or useful, there are generally five energy paths in and out of a specific energy function. These energy paths include: (i) the path of input energy used or purchased to achieve the energy function, (ii) the path of output energy for performing useful work, i.e., the work the machine was intended to perform, (iii) the path of waste energy, or energy loss, typically a function of the second law of thermodynamics, while attempting to perform the useful work, (iv) the path of any input signal energy used to direct other energy paths, and (v) the path of any external input energy from the environment.
At times, a machine product or process may generate energy losses or leaks that manifest themselves in the form of vibrations, noise, fluid leaks, overheating or wear. For these energy leak problems, conventional diagnostic and measurement systems typically measure the waste energy itself by measuring the magnitude of vibrations or noise, the leak rate, the time to overheat or the amount of wear. For example, using a traditional approach for diagnosing the cause of a product or process malfunction, the presence of an undesirable event (or the lack of a desirable event), such as a fluid leak in a bolted flange and seal arrangement (FIG. 1), is detected and measured directly with respect to the magnitude of the leak in order to determine the feature or property of the particular component responsible for causing the event. As a result of using this direct measurement approach, two systems that do not leak would appear to have no difference with respect to their tendency to leak.
Traditional approaches for determining the potential reliability of a product or process often expose a group of products or processes to a specific test environment and compare their performance to a requirement. This requirement is often in a “no failures allowed” format. The presence of an undesirable event, such as the fluid leak in the bolted flange and seal arrangement as described above, at any point during the test would be categorized as a failure. As a result, systems which do not experience a leak would appear to have no difference with respect to their tendency to leak and would therefore be thought of as reliable.
Events can be catastrophic (e.g., something breaks) or they can be simple malfunctions. It is possible that a catastrophic failure at a component level can cause a malfunction at a system level. All events, whether catastrophic or malfunctions, are driven by four energy functions, and each of those four energy functions is in turn driven by individual features and/or properties of a product or process, or combinations thereof. Catastrophic events are traditionally difficult to measure because they have occurred in the past. Moreover, traditional methods, including those described above, often rely solely on an attribute measurement system for catastrophic failures (i.e., broken vs. not broken) providing little leverage to converge onto the root cause of the failure.
Therefore, there is a long felt yet unmet need for systems and methods that use an energy function model to identify questions concerning a product or process malfunction, rapidly and easily answer those questions, and isolate the root cause of a malfunction event to a subset of the product or process represented by the energy function model. A series of the questions identified act as a progressive search to converge on the feature or property that can be changed or controlled to manage the energy responsible for the malfunction.